Alarm system



Dec. 8, 1959 w. JOHNSON, JR 2,916,730

ALARM SYSTEM Filed Dec. 9, 1955 2 Sheets-Sheet 1 INVENTOR.

AT TO QM EYS wAL-wen. JouufiON, An.

Dec. 8, 1959 w. JOHNSON, JR

ALARM SYSTEM Filed D90. 9, 1955 2 sheets -sheet 2 United States PatentALARM SYSTEM Walter Johnson, Jr., Radnor, Pa.

Application December 9, 1955, Serial No. 552,162

2 Claims. (Cl. 340227) This invention relates to an improved alarmsystem having a central station at which the incidence of and thelocation of a fire or a burglary in progress is shown.

The primary object of the invention is to provide a simpler, moreefficient, and more practical system of this kind having a singleaudible alarm signal and which combines in the system means fordetecting and indicating the location of a fire, and means for detectingand indicating the location of an attempted burglary entrance ofpremises having a single audible alarm signal, means for detecting afire and also means for detecting a burglary or attempted burglary.

Another object of the invention is to provide a system of this kindwhich is simple and reliable in 0,.era Lon, easy to maintain, repair andinstall, and which can be made in a rugged and serviceable form atrelatively low cost.

Other important objects and advantageous features of the invention willbe apparent from t. e following description and the accompanyingdrawing, wherein, for purposes of illustration only, a s ecific form ofthe invention is set forth in detail.

In the drawings:

Figure 1 is a perspective view of a signaling and annunciator unit,central station unit and a group of thermally actuated circuit closersassociated therewith in accordance with the present invention;

Figure 2 is a vertical longitudinal sectional view taken substantiallyon the line 22 of Figure 1;

Figure 3 is a horizontal sectional view taken substantially on the line33 of Figure 2; and

Figure 4 is a wiring diagram.

Referring to the drawings in detail, the illustrated system involves acentral station unit 9 comprising an elongated rectangular cabinet 10provided with a transparent cover 12 and with a partition 11 traversedby a row of electric annunciator bulbs 14, visible through the cover 12along one side of the cabinet. A fire indicating bulb 16 and a burglaryentrance indicating visual signal bulb 18 traverses the partition 11near one end of the cabinet and are visible through the transparentcover 12. A pilot light bulb 2i) traverses the partition 11 and isvisible through the transparent cover 12 to indicate that the system isin working order. The system includes thermally actuated circuit closers22 which are located at selected stations within a structure and eachcomprises a middle or first contact 24, and outer or second and thirdcontacts 26 and 28, contained within a housing 29. These contacts areadapted to be bridged by a bridging contactor 30 which is conventionallyactuated by any suitable thermally responsive element such as anexpanding bellows 32. As many thermally responsive circuit closers 22 asthere are annunciator lamps 14 are provided.

A suitable source of electrical energy such as a transformer 34 ismounted within the cabinet 10 and is connected by a conventionalflexible cable 36 and connector plug 38 to a conventional currentoutlet. One side of the secondary of the transformer 34 is connected bya 2,916,730 Patented Dec. 8-, 1959 conductor 40 to ground while theremaining side is connected by a fuse 42 with one side of a manuallyactuated control switch 44 by means of which the alarm system may beconnected to or disconnected from the transformer 34. The remaining sideof the switch 44 is connected to one side of the pilot bulb 20, whoseremaining side is grounded at 45 so that when the switch 44 is closed,the pilot lamp 20 will be illuminated and indicate an operativecondition of the system. The side of the switch 44 that is connected tothe pilot lamp 20 is con-. nected by a wire 47 to the middle contact 24of each of the thermally responsive switches 22.

A manual testing switch 46 has one side thereof connected to the wire 47and its other side connected to one side 48 of an audible signal 50,whose other side is grounded at 49. It will thus be seen that when theswitch 46 is closed and the switch 44 is closed, the audible signal50will be set into operation so that a test of the operativeness of theaudible signal may be made by closing the switch 46 when the switch 44is closed.

The third contact 28 of each thermal circuit closer 22 is connected by awire 51 to one side of an annunciator bulb 14 while the remaining sidesof these bulbs are grounded at 53, so that when a bridging contactor 30is engaged with the contacts 24, 26 and 28 under the influence ofthermal expansion of the member 32, a ciruit will be closed through arelated annunciator bulb 14 and will flow from the source 34 through theswitch 44 and (ontact 24 through the contact 28 and thence through itsrespective annunciator bulb 14. The fire indicating bulb 16 has one sideconnected by wires 53 to the contacts 26 of all of the thermallyactuated units 22 and its remaining side is grounded at 57 so that whena bridging contactor 30 engages the contacts 24, 26 and 28, the fireindicating lamp 16 will be illuminated and indicate that a fire is inprogress in a Zone indicated by an annunciator bulb 14.

Mounted at suitable stations throughout a building are pairs of burglarycontacts 52 and 54. The contacts 52 are connected to the middle contacts24 of the thermal units 22 by wires 54 which are also connected to awire 61 which is connected to the switch 44 and the transformer 34. Thecontacts 52 and 54 are bridgeable by means of contactors 56 which areelectrically connected together by a wire 63, and by wires 65 and 67 tothe terminal 48 of the audible signal 50, and to one side of theburglary indicating bulb 18, whose opposite side is grounded at 69. Itwill thus be seen that when any one of the manual contactors 56 isadvanced into bridging contact with a pair of contacts 52 and 54, theannunciator bulb 14 related thereto will be illuminated along with theburglary indicating bulb 18 and the audible signal 50.

It will be understood, of course, that the cabinet 10 is located at somecentral station where the sound produced by the audible signal 50 willarouse an attendant who, by glancing at the cabinet, will be able notonly to locate the area in which the fire or burglary is in progress,but to readily detect whether it is a fire or a burglary by theillumination of either the visual signal bulb 16 or the visual signalbulb 18, and act accordingly.

By thus combining the visual fire or burglary indicating means withaudible signal means, it will be obvious that but a minimum amount ofwiring is required in order to completely protect a structure from theravages of fire or burglary.

While in the foregoing there has been shown and described the preferredembodiment of this invention, it is to be understood that minor changesin the details of construction, combination and arrangement of parts maybe resorted to without departing from the spirit and scope of theinvention as claimed.

What is claimed is:

1. In a fire alarm system, a thermally actuated normally open switchadapted to be disposed at a selected station of a building, said switchincluding three fixed contacts arranged in aligned spaced relation and athermally responsive contact movable into closing relation with allthree of said fixed contacts simultaneously, a source of current, afirst conductor means connecting one side of said source to one of saidcontacts, an audible signal, a second conductor means connecting saidaudible signal to another one of said contacts, a visual annunciator, athird conductor means connecting said annunciator to the remaining oneof said contacts, a testing switch including a pair of terminals, afourth conductor means connecting one of the terminals of said-testingswitch to said first conductor means, a fifth conductor means connectingthe other of the terminals of said testing switch to said visualannunciator, the other side of said source having a ground connection tosaid audible signal and said annunciator.

2. In a fire alarm system, a thermally actuated normally open switchadapted to be disposed at a selection station of a building, said switchincluding three fixed contacts arranged in aligned spaced relation and athermally responsive contact movable into closing relation with respectto all of said three fixed contacts simultaneously, a source of current,a first conductor means connecting one side of said source to one ofsaid contacts, an audible signal, a visual signal, a second conductormeans connecting said audible and visual signals to another one of saidcontacts, a visual annunciator, a third conductor means connecting saidannunciator to the remaining one of said contacts, a testing switchincluding a pair of terminals, a fourth conductor means connecting oneof the terminals of said testing switch to said first conductor means, afifth conductor means connecting the other of the terminals of saidtesting switch to said visual annunciator, the other side of said sourcehaving a ground connection to said visual signal, said audible signal,and said annunciator.

References Cited in the file of this patent UNITED STATES PATENTS1,536,933 Rose May 5, 1925 1,996,308 Shyrock Apr. 2, 1935 2,074,262Grant Mar. 16, 1937 2,599,623 Forrester June 10, 1952 2,624,792 FruhJan. 6, 1953

